Wow, I've been lazy. My last post was over a month ago.
I saw Prometheus a few days ago. It was good.
SPOILER ALERT! Do not read any further unless you have already seen the movie!
The idea that humankind is not native to Earth, but that it instead descended from an alien species is not a new one, but it's probably not true.
We have ample genetic and fossil evidence to support the idea that we instead share common ancestors with apes, and with many other species on Earth. In order to be descended from aliens, pretty much life on Earth would have to also be descended from the same aliens, because we share DNA with reptiles and fish, and that wasn't the implication of the movie.
I would love for us to be an alien species. I would love for our long-lost cousins to land on planet Earth and give us super-advanced technology that would change the course of our civilization. But the truth is, if there are aliens out there, they are most certainly not related to us, and will most likely try to do to us what Europeans did to native Americans; that is to say exterminate our kin so they can steal our natural resources, and force us onto reservations where we can sell discounted gasoline and cigarettes at tax-free casinos a few hundred years later. That's a joke of course.
The point is, yes, the movie is entertaining; go see it now. However, I must disagree with the posited theory contained therein that homo sapiens is not native to Earth. We most certainly originated on Earth, and did not have designers. We evolved from ancestral species, that much is for sure.